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What Hormone Causes Glucose To Be Removed From The Blood And Stored

Hormones And The Endocrine System

Hormones And The Endocrine System

Function: The co-ordination of body organs, so as to operate as part of an integrated system. The endocrine system is often compared with the nervous system, which also has the function of co- ordination and passing "instructions", but by an independent mechanism. This is achieved by the production of HORMONES ("chemical messengers"): - organic compounds (i.e. fairly complex molecules, based on carbon - often proteins, peptides, steroids/sterols [lipids] ) - produced by various glands in different parts of the body - endocrine glands, also called ductless glands (because they have no duct or tube to pipe their secretions to a release point) - instead they are transported in the blood - so they travel at the "speed of blood": slower than nervous impulses - cause longer lasting effects: gradually eliminated from body in urine - delivered by blood circulation to all parts of the body - each has a specific target organ/organs with specific receptors on their cell surfaces which detect the presence of the hormone - produced in small quantities (mg/µg/ng/pg) - often have profound physiological effects - used to stabilise the body's internal environment by regulating its physiology (i.e. have a role in homeostasis) - also co-ordinate longer term processes, e.g. sexual development, growth. Hormones have the function of controlling body processes which require several organs of the body to interact for a combined effect. For example, sexual development at puberty, and events during the menstrual cycle and pregnancy need general co-ordination over a long period of time, but the body's response to variation in levels of carbohydrate in the body, and reaction to stressful situations are much quicker responses. Hormonal responses are not as quick as nervous responses, but they can Continue reading >>

The Endocrine Pancreas

The Endocrine Pancreas

Cells and Secretions of the Pancreatic Islets The pancreatic islets each contain four varieties of cells: The alpha cell produces the hormone glucagon and makes up approximately 20 percent of each islet. Glucagon plays an important role in blood glucose regulation; low blood glucose levels stimulate its release. The beta cell produces the hormone insulin and makes up approximately 75 percent of each islet. Elevated blood glucose levels stimulate the release of insulin. The delta cell accounts for four percent of the islet cells and secretes the peptide hormone somatostatin. Recall that somatostatin is also released by the hypothalamus (as GHIH), and the stomach and intestines also secrete it. An inhibiting hormone, pancreatic somatostatin inhibits the release of both glucagon and insulin. The PP cell accounts for about one percent of islet cells and secretes the pancreatic polypeptide hormone. It is thought to play a role in appetite, as well as in the regulation of pancreatic exocrine and endocrine secretions. Pancreatic polypeptide released following a meal may reduce further food consumption; however, it is also released in response to fasting. Regulation of Blood Glucose Levels by Insulin and Glucagon Glucose is required for cellular respiration and is the preferred fuel for all body cells. The body derives glucose from the breakdown of the carbohydrate-containing foods and drinks we consume. Glucose not immediately taken up by cells for fuel can be stored by the liver and muscles as glycogen, or converted to triglycerides and stored in the adipose tissue. Hormones regulate both the storage and the utilization of glucose as required. Receptors located in the pancreas sense blood glucose levels, and subsequently the pancreatic cells secrete glucagon or insulin to mai Continue reading >>

Insulin Regulates Not Just Blood

Insulin Regulates Not Just Blood

Put the Power of MHCP in Your Blood Sugar But Fatty Acids As Well The cinnamon extract MHCP mimics insulin with regard to glucose. Does it do the same with regard to fatty acids? By Aaron W. Jensen, Ph.D. nsulin is one of the most intensively studied proteins in medicine. A wealth of research from laboratories throughout the world over the past 80 years has helped to elucidate the role that this hormone plays in regulating blood glucose (blood sugar) levels. We know that when insulin production is impaired - or, just as importantly, when our cells become resistant to the effects of insulin - our blood glucose levels can become dangerously elevated - a condition called hyperglycemia. The eventual result is the sinister disease diabetes mellitus, or diabetes for short. By far the most common form of this disease is type 2, or age-related, diabetes. All cells in the body require glucose as a source of chemical energy - but to varying degrees. For most tissues, glucose is the primary energy source, and for the brain it is virtually the only source. And although glucose is the preferred energy source for the muscles, they (and many other tissues) are also equipped to use other fuels, notably fatty acids. These organic compounds, which are sometimes loosely referred to as fats, are components of true fats. They are derived from plant and animal fats in our diet and are precursors to the human fats made by our own bodies. As you already know from the title of this article, insulin regulates not just glucose, but fatty acids as well. We'll soon see how it does that - but why is it important? Because fatty acids are among the most basic of all nutrients. Paradoxically, however, some are potentially harmful to our health (particularly our heart health), whereas others are decided Continue reading >>

Review The Glut4 Glucose Transporter

Review The Glut4 Glucose Transporter

Figure 1. Structural Features of the Insulin-Regulated GLUT4 Glucose Transporter Protein The unique sensitivity of GLUT4 to insulin-mediated translocation appears to derive from sequences shown in the N-terminal (required phenylalanine) and COOH-terminal (required dileucine and acidic residues) regions. These sequences are likely involved in rapid internalization and sorting of GLUT4 in intracellular membranes termed GLUT4 storage vesicles (GSV), as outlined in Figure 3. See text for further details. GLUT4 Is a Key Determinant of Glucose Homeostasis A central role for GLUT4 in whole-body metabolism is strongly supported by a variety of genetically engineered mouse models where expression of the transporter is either enhanced or ablated in muscle or adipose tissue or both. The whole-body GLUT4−/− mouse itself may be less informative due to upregulation of compensatory mechanisms that may promote survival of these animals (Katz et al., 1995; Stenbit et al., 1996). However, heterozygous GLUT4+/− mice that display decreased GLUT4 protein in muscle and adipose tissue show the expected insulin resistance and propensity toward diabetes that is consistent with a major role of GLUT4 in glucose disposal (Rossetti et al., 1997; Stenbit et al., 1997; Li et al., 2000). Interestingly, overexpression of GLUT4 expression in skeletal muscle of such GLUT4+/− animals through crosses with transgenic mice normalizes insulin sensitivity and glucose tolerance (Tsao et al., 1999). Transgenic mice expressing high levels of GLUT4 in adipose tissue (Shepherd et al., 1993; Tozzo et al., 1995) or in skeletal muscle (Tsao et al., 1996, 2001) in turn are both highly insulin sensitive and glucose tolerant. Conversely, conditional depletion of GLUT4 in either adipose tissue or skeletal muscle c Continue reading >>

Human Physiology/the Endocrine System

Human Physiology/the Endocrine System

The endocrine system is a control system of ductless glands that secrete hormones within specific organs. Hormones act as "messengers," and are carried by the bloodstream to different cells in the body, which interpret these messages and act on them. It seems like a far fetched idea that a small chemical can enter the bloodstream and cause an action at a distant location in the body. Yet this occurs in our bodies everyday of our lives. The ability to maintain homeostasis and respond to stimuli is largely due to hormones secreted within the body. Without hormones, you could not grow, maintain a constant temperature, produce offspring, or perform the basic actions and functions that are essential for life. The endocrine system provides an electrochemical connection from the hypothalamus of the brain to all the organs that control the body metabolism, growth and development, and reproduction. There are two types of hormones secreted in the endocrine system: Steroidal (or lipid based) and non-steroidal, (or protein based) hormones. The endocrine system regulates its hormones through negative feedback, except in very specific cases like childbirth. Increases in hormone activity decrease the production of that hormone. The immune system and other factors contribute as control factors also, altogether maintaining constant levels of hormones. Exocrine Glands are those which release their cellular secretions through a duct which empties to the outside or into the lumen (empty internal space) of an organ. These include certain sweat glands, salivary and pancreatic glands, and mammary glands. They are not considered a part of the endocrine system. Endocrine Glands are those glands which have no duct and release their secretions directly into the intercellular fluid or into the blo Continue reading >>

Picture Of Blood

Picture Of Blood

Blood is a constantly circulating fluid providing the body with nutrition, oxygen, and waste removal. Blood is mostly liquid, with numerous cells and proteins suspended in it, making blood "thicker" than pure water. The average person has about 5 liters (more than a gallon) of blood. A liquid called plasma makes up about half of the content of blood. Plasma contains proteins that help blood to clot, transport substances through the blood, and perform other functions. Blood plasma also contains glucose and other dissolved nutrients. About half of blood volume is composed of blood cells: • Red blood cells, which carry oxygen to the tissues • White blood cells, which fight infections • Platelets, smaller cells that help blood to clot Blood is conducted through blood vessels (arteries and veins). Blood is prevented from clotting in the blood vessels by their smoothness, and the finely tuned balance of clotting factors. Blood Conditions Hemorrhage (bleeding): Blood leaking out of blood vessels may be obvious, as from a wound penetrating the skin. Internal bleeding (such as into the intestines, or after a car accident) may not be immediately apparent. Hematoma: A collection of blood inside the body tissues. Internal bleeding often causes a hematoma. Leukemia: A form of blood cancer, in which white blood cells multiply abnormally and circulate through the blood. The abnormal white blood cells make getting sick from infections easier than normal. Multiple myeloma: A form of blood cancer of plasma cells similar to leukemia. Anemia, kidney failure and high blood calcium levels are common in multiple myeloma. Lymphoma: A form of blood cancer, in which white blood cells multiply abnormally inside lymph nodes and other tissues. The enlarging tissues, and disruption of blood's Continue reading >>

You And Your Hormones

You And Your Hormones

What is glucagon? Glucagon is a hormone that is involved in controlling blood sugar (glucose) levels. It is secreted into the bloodstream by the alpha cells, found in the islets of langerhans, in the pancreas. The glucagon-secreting alpha cells surround a core of insulin-secreting beta cells, which reflects the close relationship between the two hormones. Glucagon’s role in the body is to prevent blood glucose levels dropping too low. To do this, it acts on the liver in several ways: It stimulates the conversion of stored glycogen (stored in the liver) to glucose, which can be released into the bloodstream. This process is called glycogenolysis. It promotes the production of glucose from amino acid molecules. This process is called gluconeogenesis. It reduces glucose consumption by the liver so that as much glucose as possible can be secreted into the bloodstream to maintain blood glucose levels. Glucagon also acts on adipose tissue to stimulate the breakdown of fat stores into the bloodstream. How is glucagon controlled? Glucagon works along with the hormone insulin to control blood sugar levels and keep them within set levels. Glucagon is released to stop blood sugar levels dropping too low, while insulin is released to stop blood sugar levels rising too high. Release of glucagon is stimulated by low blood glucose (hypoglycaemia), protein-rich meals and adrenaline (another important hormone for combating low glucose). Release of glucagon is prevented by raised blood glucose and carbohydrate in meals, detected by cells in the pancreas. In the longer-term, glucagon is crucial to the body’s response to lack of food. For example, it encourages the use of stored fat for energy in order to preserve the limited supply of glucose. What happens if I have too much glucagon? Continue reading >>

Glucose Homeostasis

Glucose Homeostasis

Glucose Homeostasis Most animals, are obliged to catabolize food and use the freed energy to drive anabolic synthesis. In other words, we consume complex substances, break them down to release energy and we use that energy to fuel, build and repair our own cellular components. From molds to mammals, glucose is quantitatively the most important fuel source for life on earth. It is the primary fuel for our nervous system and the preferred energy source during initial physical activity. Glucose is also an important building block for cellular structures. When the body needs to produce lactose, glycoproteins and glycolipids, they are all synthesized using glucose. We have two sources of glucose: 1) food, 2) products of metabolism. Food contains carbohydrates, lipids, proteins etc. Dietary carbohydrates are digested to yield simple sugar molecules in the gut. Simple sugars like glucose, galactose and fructose pass from the intestinal lumen to the liver via the portal circulation. Glucose makes up about 80% of absorbed dietary sugars. Galactose and fructose make up the difference. In addition to dietary carbohydrates, we can synthesize glucose from non carbohydrate products of metabolism (gluconeogenesis). Gluconeogenesis is particularly important during fasting and starvation because the testes, erythrocytes, kidney, lens and cornea are dependant upon glucose as their sole energy source. Glucose is also the primary fuel for the brain but if glucose is low it can use ketone bodies to replace about 20% of the its glucose requirement. Gluconeogenesis can provide the nervous system with a steady supply of glucose even during prolonged fasting. The activities of daily life require us to consume more nutrients at each meal than we can use immediately. However, the body can store o Continue reading >>

Insulinomas Faqs

Insulinomas Faqs

An insulinoma is a tumour found on the pancreas and is known as a pancreatic endocrine tumour. These tumours release the hormone insulin which can affect blood sugar levels causing hypoglycaemic (hypos) episodes. Insulinomas can be benign or malignant. Insulinomas are quite rare and less than 10% are malignant. They are more common in the fifth decade of life and there is a higher incidence in women than men. Approximately 10% have multiple tumours. Approximately 5% of insulinomas are as a result of MEN1 syndrome. Multiple endocrine neoplasia type 1 (MEN1 syndrome is an extremely rare condition caused by a faulty gene which can be inherited and causes a number of tumours to develop in the endocrine system. These tumours can be benign or malignant. If your consultant suspects that you may have MEN1 you will be offered a blood test to estimate levels of calcium and certain hormones in the blood. If the condition is confirmed you will be offered genetic counselling and a treatment plan will be designed for you. Arrangements will also be made for your children and siblings to be tested for MEN1. Insulin is a peptide hormone responsible for regulating fat and carbohydrate metabolism in the body. Insulin is produced by the pancreas, which lies behind the stomach. Insulin’s role is to remove excess glucose (sugars) from the blood which could be toxic. Once glucose levels drop to the normal range, insulin release slows down or stops. However insulinomas keep releasing insulin even when your blood sugar drops too low. High blood insulin levels cause low blood sugar levels (hypoglycaemia or hypos as they are generally known). Hypos may be mild making you feel anxious or hungry or can be severe leading to a loss of consciousness or seizures. The initial symptoms for an insulinom Continue reading >>

Glycogen Breakdown

Glycogen Breakdown

Glycogen Structure Glycogen is a polymer of glucose (up to 120,000 glucose residues) and is a primary carbohydrate storage form in animals. The polymer is composed of units of glucose linked alpha(1-4) with branches occurring alpha(1-6) approximately every 8-12 residues. The end of the molecule containing a free carbon number one on glucose is called a reducing end. The other ends are all called non-reducing ends. Related polymers in plants include starch (alpha(1-4) polymers only) and amylopectin (alpha (1-6) branches every 24-30 residues). Glycogen provides an additional source of glucose besides that produced via gluconeogenesis. Because glycogen contains so many glucoses, it acts like a battery backup for the body, providing a quick source of glucose when needed and providing a place to store excess glucose when glucose concentrations in the blood rise. The branching of glycogen is an important feature of the molecule metabolically as well. Since glycogen is broken down from the "ends" of the molecule, more branches translate to more ends, and more glucose that can be released at once. Liver and skeletal muscle are primary sites in the body where glycogen is found. Overview The primary advantages of storage carbohydrates in animals are that 1) energy is not released from fat (other major energy storage form in animals) as fast as from glycogen; 2) glycolysis provides a mechanism of anaerobic metabolism (important in muscle cells that cannot get oxygen as fast as needed); and 3) glycogen provides a means of maintaining glucose levels that cannot be provided by fat. Breakdown of glycogen involves 1) release of glucose-1-phosphate (G1P), 2) rearranging the remaining glycogen (as necessary) to permit continued breakdown, and 3) conversion of G1P to G6P for further metab Continue reading >>

Unit 8-endocrine System

Unit 8-endocrine System

1. Digestive Hormones: The best known digestive hormones are those of the stomach and duodenum. There may be others produced in other parts of the intestine as well, but evidence is lacking. Gastrin, the hormone produced in the stomach, favors the production of gastric acid secretions. The hormone is produced in response to vagal stimulation, which also produces gastric acid and pepsin secretion. However, it is produced even after the vagus is cut, meaning that local factors must also be involved. The most important of these is apparently protein in the stomach. The breakdown of protein, initiated by the process set in motion by astrin or the vagus results in polypeptide formation; these further stimulate the secretion of gastrin; and fairly soon, the gastric secretion is maximal. The continued breakdown of foods through mechanical activity of the stomach assisted by the gastric secretions reduces the stomach contents to a point where they can be forced through the pylorus into the duodenum. Until this time, it might seem that gastrin, rather than quenching the initiating stimulus, enhanced it. When, however, it is recalled that the taking of food results in the emptying of the stomach, it is quite clear that the stimulus, taking food into the stomach, is neutralized by the response, emptying the stomach. It may be noted that alcohol also causes gastrin release. The widespread use of pre-dinner drinks has been interpreted to indicate that the digestive virtues of alcohol are somehow known to most people. Unfortunately for this argument, breakfast and lunch are digested by the same people who require alcoholic drinks before dinner without any discernable difficulties. It may be suspected that alcohol before dinner serves other digestive purposes. The acid-food-pepsin mix Continue reading >>

Insulin

Insulin

History Insulin is a hormone secreted by the pancreas gland, one of the glands in the endocrine system. Insulin, working in harmony with other hormones, regulates the level of blood sugar (glucose). Endocrine glands are ductless glands; that is, they pour their products (hormones) directly into the bloodstream. The pancreas, a gland in the upper abdomen, has cells within it that secrete insulin directly into the bloodstream. An insufficient level of insulin secretion leads to high blood sugar, a disease called diabetes mellitus or, simply, diabetes. Specifically, diabetes is a metabolic disease caused by the body’s inability to use the hormone insulin to effectively convert carbohydrates into the simple sugar glucose that cells store and use to perform vital functions. Without glucose to fuel their activity, the cells use fat instead, producing ketones as a waste product. Ketones build up in blood and disrupt brain functions. Common signs of diabetes are excessive thirst, urination, and fatigue. The disease can also cause vision loss, decreased blood supply to hands and feet, pain, and skin infections. If left untreated diabetes can induce coma and cause death. Diabetes often runs in families. In the United States about 10% of the Caucasian population suffers from diabetes, and it is even more common among African-American, Mexican-American, and certain Native American groups. The sixth leading cause of death in the United States, diabetes remains a major health problem. According to the American Diabetes Association, about 20.8 million children and adults (about 7% of the U.S. population), as of 2006, suffer from diabetes mellitus. About 14.6 million people have been diagnosed with diabetes. However, about 6.2 million people (about one-third) do not know that they ha Continue reading >>

The Pituitary Gland

The Pituitary Gland

This leaflet gives a brief overview of the pituitary gland and the hormones it makes. What is the pituitary gland? The pituitary gland is a gland in the brain which produces chemicals called hormones (an endocrine gland). Hormones are chemical messengers which help different organs in the body communicate with each other. The pituitary gland is one part of a messenger system. The pituitary gland helps to control your body's functions by releasing hormones into your bloodstream. These hormones are transported in your blood to their target. Here they usually cause the release of a second hormone. The target can either be specialised endocrine glands or other types of body tissue such as groups of cells. The pituitary gland is sometimes called the master gland because it controls several other hormone-releasing glands. Some of the glands the pituitary gland controls are the thyroid gland, the ovaries, the testicles (testes) and the adrenal glands. Where is the pituitary gland found? About the size of a pea, the pituitary gland is found at the base of the brain, behind the bridge of your nose. The pituitary gland is very close to another part of the brain, called the hypothalamus. The pituitary gland has two main parts: The part of the pituitary gland at the front, called the anterior pituitary. The part of the pituitary gland at the back, called the posterior pituitary. These two parts release different hormones which are aimed at different parts of the body. There is also a section between the two main parts, called the intermediate part, which releases a single hormone. The final part of the pituitary gland is the stalk, which connects the posterior pituitary to the hypothalamus. How does the pituitary gland work? Your body is in a constant state of change. Your heart ra Continue reading >>

Muhammad Z. Shrayyef And John E. Gerich

Muhammad Z. Shrayyef And John E. Gerich

Chapter 2 Normal Glucose Homeostasis Glucose: From Origins to Fates Arterial plasma glucose values throughout a 24-h period average approximately 90 mg/dl, with a maximal con- centration usually not exceeding 165 mg/dl such as after meal ingestion1 and remaining above 55 mg/dl such as after exercise2 or a moderate fast (60 h).3 This relative stability contrasts with the situation for other substrates such as glycerol, lactate, free fatty acids, and ketone bodies whose fluctuations are much wider (Table 2.1).4 This narrow range defining normoglycemia is maintained through an intricate regulatory and counterregula- tory neuro-hormonal system: A decrement in plasma glucose as little as 20 mg/dl (from 90 to 70 mg/dl) will suppress the release of insulin and will decrease glucose uptake in certain areas in the brain (e.g., hypothalamus where glucose sensors are located); this will activate the sympathetic nervous system and trigger the release of counterregulatory hormones (glucagon, catecholamines, cortisol, and growth hormone).5 All these changes will increase glucose release into plasma and decrease its removal so as to restore normoglycemia. On the other hand, a 10 mg/dl increment in plasma glucose will stimulate insulin release and suppress glucagon secretion to prevent further increments and restore normoglycemia. Glucose in plasma either comes from dietary sources or is either the result of the breakdown of glycogen in liver (glycogenolysis) or the formation of glucose in liver and kidney from other carbons compounds (precursors) such as lactate, pyruvate, amino acids, and glycerol (gluconeogenesis). In humans, glucose removed from plasma may have different fates in different tissues and under different conditions (e.g., postabsorptive vs. postprandial), but the pathw Continue reading >>

How Sugar Makes You Fat

How Sugar Makes You Fat

Look at how many grams of sugar are in what you’re eating (on the nutritional label). Now divide that number by 4. That’s how many teaspoons of pure sugar you’re consuming. Kinda scary, huh? Sugar makes you fat and fatfree food isn’t really free of fat. I’ve said it before in multiple articles, but occasionally, I’ve had someone lean over my desk and say “How in the heck does sugar make you fat if there’s no fat in it?”. This article will answer that puzzler, and provide you with some helpful suggestions to achieve not only weight loss success, but improved body health. First, let’s make some qualifications. Sugar isn’t inherently evil. Your body uses sugar to survive, and burns sugar to provide you with the energy necessary for life. Many truly healthy foods are actually broken down to sugar in the body – through the conversion of long and complex sugars called polysaccharides into short and simple sugars called monosaccharides, such as glucose. In additions to the breakdown products of fat and protein, glucose is a great energy source for your body. However, there are two ways that sugar can sabotage your body and cause fat storage. Excess glucose is the first problem, and it involves a very simple concept. Anytime you have filled your body with more fuel than it actually needs (and this is very easy to do when eating foods with high sugar content), your liver’s sugar storage capacity is exceeded. When the liver is maximally full, the excess sugar is converted by the liver into fatty acids (that’s right – fat!) and returned to the bloodstream, where is taken throughout your body and stored (that’s right – as fat!) wherever you tend to store adipose fat cells, including, but not limited to, the popular regions of the stomach, hips, but Continue reading >>

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